This invention relates generally to working trim for use with locks and more particularly to working trim for use with mortise locks.
In the past, one embodiment of working trim utilized a threaded square spindle which extended out from an adapter plate having a bushing portion thereon which was attached to the door. An internally threaded adjustable shank, on which the door knob was mounted and retained thereon by a knob retainer, was threaded on the spindle until it fit snugly in the bushing. A set screw threadly extended through the shank and was tightened against the spindle with the set screw bottoming against one of the flat sides of the square spindle. In use, by turning the door knob the latch bolt of the mortise lock could be operated due to the interconnection of the knob, adjustable shank, and spindle.
The threaded spindle and shank provided a means for adjusting for various door thicknesses. However, the torque, by repeated turning of the door knob, could result in the set screw damaging the spindle and the knob and shank adapter might loosen up. This problem could be compounded if the set screw was not bottomed on a flat side of the spindle, but rather, bottomed on one of the corners of the square spindle.